import java.math.BigInteger;
import java.util.Scanner;

/*
    二进制求和(位运算)
 */
public class BinarySum {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String a = sc.nextLine();
        String b = sc.nextLine();
        BigInteger x = new BigInteger(a, 2);
        BigInteger y = new BigInteger(b, 2);
        BigInteger zero = new BigInteger("0", 2);
        BigInteger carry, answer;
        while (y.compareTo(zero) != 0) {
            answer = x.xor(y);
            carry = x.and(y).shiftLeft(1);
            x = answer;
            y = carry;
        }
        System.out.println(x.toString(2));
    }
}
